SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ab34ef232dd8b6418bbee24ce9a2f606cc31225167898f6aaa7dba479934956' 
  AND token = '3JzhwPomOgEd4Bvkw1PaZjWxT9Z3rW6kBHYFPRxSQAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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