SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ae14d43d9831393835dd15d77ea9986c6bb52dec00d9bd64056e6bf44893357' 
  AND token = 'ytPUWaVtyRmV3wiRp2yJZ/wVjtCXa6abcay6OQ3FCmw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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