SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36801ce636b300f52cb992a6ba5f3e0925e3da0982a7bc8de7d349139b31a1d7' 
  AND token = 'Q3z/xpGuTqHCiYUw+i/PYJqUMMEPwqDWMRzweZoQPvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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