SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '893ed0dd38eaa431abee2152cf5fdb51bcee98b60e1e2851fb98894d6edcda37' 
  AND token = 'jPKQumTMCVcWkyyaPQvCrFUvwnl2WCY1Ny52mgCRhRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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