SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '247089f9ae6310bea6938cda71ea44d643c7a566c981aa1dd5529f535b06c915' 
  AND token = 'fGljxGhHWtEwm5KpDm/wsuQZ+9tqrbbxv3OTrIIus0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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