SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03f3d680fc7de80a5a93e2a7275240fc5032dc49800bf7d615b425a5c6dabd40' 
  AND token = '/hYsjRt1pN3X5dB8Efc40xnI7a27/2yyWE0QV33af2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}