SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '814d086ded1f441b81e43642670d5081edd915d34937564386c9fd3103955928' 
  AND token = 'MznAIwp+7dV0oskHCGfiTTHke6plhpV5kdUlXzIs9XU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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