SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f4380ce520372d1d2854056a2113b80c5d721c3072e678f4d0ef6eb952f59ba' 
  AND token = 'WRVFBi3tf1mtBb93LR5sVcRatYXHL5beH3XJnzm4xzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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