SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dee12d628a846c55d74a851d004435a477c8bfc516e6767721bf29e729b01c8' 
  AND token = 'A3qm7TIDVkJzF4GgQCPOmsUdI0EQ4rZL/CRfHUETjnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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