SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be9bb846d5c4311edaa1abbbedaa3f927b6bed50383f27647938754014231e9a' 
  AND token = 'loFAkQl2WeOOl6SdGxm12fzJLvJ3WHm6rCVVQZ/aIXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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