SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b00411b4fc59d4320a171b5f9ded7a0c08ea9f80f765e6cec2bc5f6bd553f92' 
  AND token = 'HxQOxGjgClIJRtww+tzwxA/13pcOdxzi039kQfMfZFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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