SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '209ae966f2336006b23c258b34b8c6d80f97d6d7211e15281a222c60275631e5' 
  AND token = 'UWFpcvKjx2nZebWBZBDwMMjEQ2L4q74r0TSWwWHT5wA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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