SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00d9864286ce9986f5abf7b28088119196b10e978354b54b73235dd2608d39a7' 
  AND token = 'z809FoEiLJEhtVZgFTnDXZ+a/46Zk0jlvRnDbLylrDc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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