SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b33152bc2b77ec592926593d4bf2ccaead6df76c61e7cf2b567a77de9b36cb9' 
  AND token = 'AU0DyHGBAJzWKpxlzO1rRziBfJ3nDqu1ApCpwLrTi5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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