SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4f14e1187f1c62433b4bfeb2765a28a9b3e2e1b878dc15014482e2d24b5dd17' 
  AND token = 'txnwdwv7kdcFvAoQd5SkjuiXsTPn7Qpwk6n03IYp9QA=' 
  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"
    }
  }
}