SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4519e880411a8164a862e56ade9891264209860f06cea85d39524b57c67dd457' 
  AND token = 'yl+QdPDp+l3NZ1kKnIKpkbd+Js9MKk1P5JKrwIIMm/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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