SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2000fbbec836308857e39bdbeb595567735ddff9e32d055098ddbdfd47ee09a' 
  AND token = 'zJpnJAIH/+qVM/QS0ciuQuPMai08ErTEp/u6/MhEbkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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