SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f2684d3b99ba5886992f0846b8467aa5c6588406f65e851d410e5c749dc629a' 
  AND token = 'VU3B44fWk+bvXStauUkp/qlgbJkzYve8KHojljOmUUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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