SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25f8e5a5ca501699ff9241566df7558de523d56fd44ea08b27863e44d4681bb3' 
  AND token = 'YBSKunLwpfpl0n4NvxPRv3k2Htq7+gISLRCzy3QZ3i0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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