SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a505daad10a85889517f17c70e8538850f049af68accf90fca652a5066c29b34' 
  AND token = '9nR98lvuI673NNrrwiQg5Ic8aMqgyzwVuSVMJnfyc+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}