SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '135d266b7a7ee1169a21c692129976f236691a210c524de132a66fd6ed9dd10b' 
  AND token = 'vzD0iU2jNBJPIDiichTXhyBRDoS+CmP1wf1EaAqtDas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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