SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a853c0042f8784739be579c299a0d618040f2127f4d6fa5e3513453f0edda9d' 
  AND token = 'pIpizDaW8jOKRdDj472zrpOHiNaLD8TW6S1vNdHwwjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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