SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36f0ce75e7ebf46432655e8d955d037ad276b3debeb7cac5510fc27481334ef9' 
  AND token = '/g9NGdm/sD1cH2nXrf+zAzvvgqbAckM1qGQSd931Xbc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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