SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '089f4b7d7d542a1135647050703f181802425de4e0a5c39a781495183d73a1c9' 
  AND token = 'FXa0QJgobGIy3USH5l7cf2sfJA3w+BmazNxxjuP0jEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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