SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2893b7e2973dacbb8dc8235b20f2872867bca385e757ffe4cf7505c7db07d16' 
  AND token = '4ffFfTChgZZS7HgUkXjuh7Sy6PpUEPgGxlEzUCWgFZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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