SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba448b8cae652f71998e32f1e450164ab0fb3fb5b0744052287d591fd653b8f0' 
  AND token = '6j0FphNASDpOoN9w2IrHmhPrzKHZLTUVoo/KJtxIC/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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