SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0552dfe97593e28bde8245d83c4ed7cc2c3a85c9ac4f9f4958062b1fe7f99492' 
  AND token = '4zvHVb++dwpVhqlZiZtjbO6YIr9/a+OMnimgVPqnP2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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