SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7721701997d27c0cb0e0db89b620a4aeb85359166286f6571c9f7be7591949ea' 
  AND token = '8FzZBIahhIDLZiGPSYXiO9vSQTG7gJTBhszqjJ3L/ew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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