SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a76072c27e0bf4cd16bd12ba981c2657f422639c6382ec51e4af78fe93ddf5e' 
  AND token = 'V/lDDJLfJYE2gtNvQbRn7Y8OOCKBvQYbLxRPwxi0SnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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