SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50dd8335e5c66c24e56c54702115dbcb1ec7920b30a7ff9c7b167cf5a466c0fc' 
  AND token = 'cPv0oNwbbOWF+XsUsxlSWuJds0Eoe47Ndsf7mRpNB5E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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