SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '616e3eaf757d8acba45959ad30129230c4f9fc9ac99bbc51628c4e7a6b3986e9' 
  AND token = 'ADmqJOBhf/T8bOtmz645/VIAZ75i6CIUwbIKBnHhsDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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