SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddbbccfd40fba8ad685d63827ca328b4c50b693d5ce7e9098617bf0ae1dfd56a' 
  AND token = 'eiLmZe5dE2gwRriZbuQIiCB5oxo3HrIYPxpjtpJkYZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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