SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9be77303e07fad7ed589ee8bc9d114c81d5f7562577aadefa4d142c641eb3668' 
  AND token = 'ZCpNwZ1WGOeneT3lo2K9qw1CJ3zrlWg+/r+8sHwdyVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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