SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91e8897a869bcbf9e7deb089f9918c9c9578d4391d7f5e6219febd4dcd662ac9' 
  AND token = 'Eh8lezNr5g/vhncJlby3WALpdffUmkENdY/RMNl7yFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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