SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7861024ee53143ac2f431c27cace57869237a9f12649d837a81f5604811667ce' 
  AND token = 'kTTuj4BucTGjhh+3ZprzBm4Jv0VbWskCk1CzwUvICV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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