SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab271912fb3695fa7ce4c609b54ca50a0dca744b636fad5829164584522698b3' 
  AND token = '7mZYuh+6ymQlOz5sFR5OzF3uqfozvHAn8ekCLkrZvB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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