SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fd830d56e0db960621a8aefd09be671d8d98efcb8e09e6008bd34cdc766ab2e' 
  AND token = 'Su1A3AuXBOoRgKrb6nPQ8PsZ4VftQhfvciuJknXzvyw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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