SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a586f751279376263b8b440237a82c670edab14c6ed9e83aed03bb1f5f154e1c' 
  AND token = 'qlPt2K8o/akf1YBtGsvhkNkuzACJWZpsPFqkssUk/B4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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