SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '164669c782d2998eadea4af040a1a22c3408fd094ae4cfb9e74f6836a574056c' 
  AND token = 'vO5/NpCIpAZSb0TM+LeRhFyOkbEmMSIRIETaJECjLd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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