SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '405287d15a7031c912b6ad4171bff6480176006713bca9cebaafd6333a829f85' 
  AND token = 'WhJ6HO1khK4W+TyDYYoYcVPeOMdTv4jME9sIlj+WdjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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