SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a1c13bf04c1d24242ab3ad9506301409b068b61d14162a769c6eaa97eeb7eea' 
  AND token = 'vqLa9RwT4XXiPlVu3pYM/XJ8jIGlBwZg1+y4CX0nSKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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