SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2373d9f202156d6c80f50211e68a04271d88266fe4c71c7e8b43656c2bb0109f' 
  AND token = 'gSXzQYtnk/FCJKfZYvwWAmD2NAq7PwZRDc01syULSs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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