SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9584921196987d6df4bd71f5b414fcb016ae3352caddf84df02c4ecf2a42458d' 
  AND token = '8ZY8CuLfL2Cr4h+ADZ+yNqoan76hVelIr808dJjrkTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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