SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '729e534b13ed9cb3219aabdaedc54c9c5b8e0278f27676163dd5c976c025ad11' 
  AND token = 'QSGxEaDHei48LUNllPztdaf3G+/6ptIPIWETk797fKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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