SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1725c5067ab6778faacba56802a0b977640113f579b38a595cbd007d7130632' 
  AND token = 'KOSjZkhviajZVnBBMyEyT2t70XLNDreICslsyiy+dxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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