SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f3f89dd1046d7b78c0986bbae83c618bddae2e9fdc24164e6d5c72102ea1157' 
  AND token = 'gbG1FZJLAzshY8IFLUKkaOf7QrKG/16vPykuNZSvxV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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