SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddfca6b6e9ad965c7b4cc1303b427cb58b0842300e008b74ceed55322c72244d' 
  AND token = 'zKTYLC90INp+ncmzCUnuWsYRH/hewO2PgsptXAExMQg=' 
  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"
    }
  }
}