SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '932efcf915841885bab04917d7d1f183599a9be2bb61c13afc0bb735a47b6220' 
  AND token = 'XsPoX/GCyOqq6jahqLHDXiLRjPzPSvzDu11cbcJjmTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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