SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2785249e32bb76f82b406be552de21e0cf8bb5fd786289f832850708329aa90' 
  AND token = '4dtHgCUWhylXhSmnRH5lHDvBpcPm1/isirdL3otBxNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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