SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c65f90ebbb9376f8d96b2268d80991cd28b507814023d984b4c4af36d6c7f4b4' 
  AND token = 'PgHqR+aVzVHxqNVvlKkY6+rNKejkpIwwU4mAYfdvtO4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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