SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8aabb875d3a1076f9558e726c5fdfe0c0bbb6f362785040459a2ade971e9f0d8' 
  AND token = '+fVRdZePvECMwxFHxNlKxc1qbVomnYaSeWsgOhIVCvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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