SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94db3ab044ae73f3cb393a2e4ada106da224d9e6cf5d4b845482f7ba6ddd8698' 
  AND token = 'n3lQCTOpKzvqXxakiB1La1zzLMK0sdAgDwJ+ylHZm4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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