SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '117ccc86c87894709a459d8f29a7a679d3561d81c4c296c37b680c66c749f56c' 
  AND token = 'e1lKYWDbtP3VYTcrYOMDvFcyVaNESdaWqCzoRehEnXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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