SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3fe912aa3741c8ce4b04170f276163e796bc24874dc56c180a924646ebf8cf9' 
  AND token = '6eNVcqDQFB4taFucbpF/WiGXwKyu6phHTullXKBfrvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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