SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35f8658edb8533b907525ab9ea351f3c39b2eb072d3f6df3a6e9be831d23dc59' 
  AND token = 'Q3WdvzaI2fCtc5FLpPJBJB2AKAfqlJoHMHlWpqwKbJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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