SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fee7a6cc32f3d317bb06ed0b6d146ec5b15d2df671f73b39e4a966f2ff08b91a' 
  AND token = 'Rq8k8ckfsUAYb2qsRM97lXECP4zeGmWI82HWiJjP3Hc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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