SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e3ed8cc155d12f45686b99fd063468797e962e28bed8cdd78a6ecd36838fa3a' 
  AND token = 'ZSMqtFrcem1SS/rL6G+UmeHSGQV1LCAAPSAwCLfxRN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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