SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6d2a223efea2ee971654c199b47a068b7b10e096a5150bfb05414b51745cf49' 
  AND token = 'kjHpuYcMMS/fM4d4HuyKYV8/pNwiB0dehEwP6mgXYyA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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