SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '837c00ac61d7932138bd33240f6d85f3ade417f99c87704880d749b49739d385' 
  AND token = 'ooO3swyxXYbHU2/0IKK+LQBCF6X8nYPP/1WfqsYBHFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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