SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f7bc1100b1acc3f4b67d601904d4996442f041b149f7d3ffae0f0f743345883' 
  AND token = 'UXhHVdeibRTVogJqwB51KsQdp4RiKUcB7Efkia+yPJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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