SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2f8373c0a3754d9143fb31f34762d5dacff255c35d3992594f60e49897bb7c90' 
  AND token = 'fTthsYON9xn/tZKoMogzJk7CCAakkUkJemFwsmvl0rk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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