SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31dfcabeaef476e2cbb060c6ea186cd188108ef27acf43003471fde00035014a' 
  AND token = 'yv3D/ZGlrJP7KLlH/wpNKzKRwkTPkgyVfI1eSlzc9a4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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