SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9508865235b966bb38b58153d77db2c549f9482d0d843688e47d40acee7cbf76' 
  AND token = 'Tolj/0wERfZmg2elKGIf32Zzw1L69uM3FH9pBaqG5Lw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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