SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14bbf1ac5bead19fecb173edfe85a0518f658ee3dec220235a8dfd79abf10efe' 
  AND token = '4f9e4zJaBepRdV4cju2BRHMfinAZjheosPzWg1QtI5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}