SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6c56cb2ffb489d21b4b7cf7a7500c4b817b8dc3828c1f6cceae1702b1002f02' 
  AND token = 'BlzB4IoSi0otNvqUO2goTxKibRljoSN6XkC1K259BxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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