SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff3e75bad6a957d3423b52e461748a00c4658a2b28fd5bcdc2e34c5bfbcfb6fa' 
  AND token = 'etaqqK+GQTWq2lBGSuO5zpHg283j9YwHLHenN73fmcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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