SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d2c7b2da389a7a609b6688fb33929e39f88c4cc3cbad9d1c8908088ba2a3ec6' 
  AND token = 'jwV5R/mxtp7J4jokkmZQ/O6/Mqv9gvP53sJ6NR+HFhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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