SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88151a942e37dc22a885719069cc5e6898fcc5c883854277aab6d8341804a42a' 
  AND token = 'yz3uzueS8QW9XrE3cvn92OVQ5hPW3RVIrKSar8m7zsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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