SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f412b398c66d160595cc048c80d81e7e8318e3a606702407d23e921057d4d2f0' 
  AND token = 'jzQzcgQsQMm+hVGaXCTh2fWoIEmyEhl4u+kvvs6SU/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}