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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd37dee3b4ea69acb12dae6bcd9dd1d5e388f57cd9e42f6aeb52f8400e860b15b' 
  AND token = 's1jS+rkCkPyWaKDjtg+BRKksVsWVrDd7Qdis9Psvdt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}