SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee24bc732663bede8874ef7c8faf2c2e7a93d47c14cfe258216958479aebd78c' 
  AND token = '6PWlAsemAiq7ODYh50jgSpY4JYjsxjnrqOkZPdA6H10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}