SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81d5fa35fdc8cdb89ed7151b09d73a0a4efa848277a1826a11d76aa8e26af35c' 
  AND token = 'REEsVsypici3amBHwEJwYavC8YgPk72Ke8BF+eVsptA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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