SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '583114b9fe16d3e607cca96caadeceae5f5e3a0455dc945762c7693201e6c3b9' 
  AND token = 'ATLstCfLfdVk/2KzH8gCbIXpfA33YMGO66p38khYtts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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