SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4753117503b75433f7fb2a568873771a1f20c9405d0a168633315bd41c1d9853' 
  AND token = 'QFvZ7Ly834OG+0RrA+uNJLrLjOAB2XCbsshsJQWycqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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