SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b4d5a9725e29a1e31ea30d6ffd7524c6157860c1c38c558b262781bf04cdf6e' 
  AND token = 'gJDm35WZz+2wGI3F1xXylppXZY1e31vmRINbjRF7shc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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