SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e10754b0659effc8f4e0ea3e27eea2b75de9299283498054ebc85fc394f2f2a' 
  AND token = 'PDnF1JLaYvEyLBLsl7+qCXjZSdX/XP0pQ/xQjpjpCIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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