SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b511a75f66fb423d2e147f439ec775db06b74ce5f7060e0c1febeb48d0ee9f0e' 
  AND token = 'UDJIor85307Omm2EAwTlV1c6tJunimmW6FafzTCTJlk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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