SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c51686c3caec3bdb267216813cb3c46927f4dd1e5b8dccc985a50ac9cc9805fa' 
  AND token = 'n26BLdko1DIw7/7ZlbAUzgyo3VYZnilIGKhWbvhZkOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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