SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba84dc12261ac98e77749bba233a448cc946d2eac5009dd8450be5c2c7cdd3bb' 
  AND token = '0eUaRZavtKMw8AiDqKvPkEbMUciNlnI+/S0xLjVOMhk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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