SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88e6823de70d96216c75ca3f418efa6aa1e340963f64c17bd28647d4f147fe1c' 
  AND token = 'kpN2CrDzNxVoBqGgDdRSDZXx9mqgCAEkqbIZ5VvY/e4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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