SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1b2f3df49e2e50ae630485bb8b7507f21f33b2e2076b3824a8d7b53b43141f8' 
  AND token = 'PrMFzsHYHaWjv94nIdkD8YbrUwwOFVNlcTBNSEB+KrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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