SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8912d6cd63b5737195ec2d57eb641191c5954814664cb0fe680d6d42487f4a9c' 
  AND token = 'r69Cq+iuXhIJUZvT9It7ps6dbR4ahzykEyRNZp+LlcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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