SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b78fb2c8b2b593216ec4e81c6141bd91dccf0a12d8bf8a59b02aa72c88d9b80' 
  AND token = 'zs91HjwsTLqNBXXViFs+Bk+tV9PopNjQLg3jHazCRYc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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