SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16040118eb6f86027eaf85fddbeb7e4adda1f92fa16582abed9da0b862723dd9' 
  AND token = 'IDuUVFsMT+PpiFQiyohSpYyrkVZOA7Gg2AYYlkav+h8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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