SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3481f45a36acd8e4f8ccf904884715d6020f9a0c6507b68ca782f133fa2f6cf' 
  AND token = 'GsTxkUkUuHY10UenJf9kXrPQZ/qpCJzXyvzfaB0eGYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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