SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f447293e699b1fb86e74d8d904ea386ba95ed5571d6512db99c45d8329531c4d' 
  AND token = 'M8nmWlaqFk8TGbmu1CkXPmnb76mputG5zNF/eY8vI5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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