SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be1a5125dd38352ce0c705a03cb2c3d327f1f00b036757e16fb295a69a8e31a0' 
  AND token = 'KZEZWQnjVMpKVhLlnUd97Z5f2nXxftDAlcLuV6De4lc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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