SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6ed59d16095a6dd33068f809e21179fcef3d4a3ec1dd3b6a531ea9aff6876f0' 
  AND token = 'G76E+cqJ90hRyICZhgxuetSmTXKKnGW4W4K06kjlgrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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