SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e31189cc38ee4fa861de0a8443e898f0da52d1bf90722d57edfb5cde68b41dc' 
  AND token = 'EQFd4CLZ6I6RVnZ1FWL1F363VAVtUPZ1dEbMjw29UFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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