SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acab6e193c64c4119a1936a2f7a4e90da48f408e78b867f5b909c234519d20b9' 
  AND token = 'DNHZ3iQBbYA3fAAOWXWw4iqVqwBKWLBi/hN8C/9QKME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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