SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '334aae4ffbf75ec94ee1f2d5efe48fe29811f82c4d8a82d513aca2c29b9503e9' 
  AND token = 'OoA8GpKHYFtLsWEA0F5JLeRaKYapoFqIHQYE5lPSsaU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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