SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b38836e18a8826339e8fbfd4808c9a4af4bfaea1472f4a2969ff23fd36999abd' 
  AND token = 'HLbQi0Nthub2SkXgDkdV09m8ZMHq8Q99Si1zlIKwa9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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