SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85f40bd7007fd775ed1ab980cffa24d71e89522ec0bada2bd4867fa733ead285' 
  AND token = 'xFOno9AAaQzOSYqiunkPAr2l5XpUxbu4YwNuBO/ua3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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