SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7951063e13f29158588ed1a17f0972fdb6046d134396b9b62e0efbad4e877881' 
  AND token = 'YlECRrEoRG9G3LZqt2L/XfaJOPxVwNLM8dSvIRGaOyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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