SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '273c970c60877c9a987451646c06b58d9c88d74f4bb3f836190d271fb54efb75' 
  AND token = 'gEtVszoIzIuqxaQU49m1NYYHkQghuVO4KdbyTKIiVE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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