SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bdceaccbe2bb0281d1aa3514d6554caf09def4b259c462438f590a33a2536d4' 
  AND token = 'VuSBHldw2fDtseUnixWCOWHUpZwU2Uiadzkvg3OXayg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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