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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6058f49a38a2d62ac9ba84009c6d8e245df5ad84a1d6d4a7e280e3ea3fbbc9a' 
  AND token = 'yTUQEFIrC5E7hU889MOoFKzM6roTkpUGxjvUFAV7nnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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