SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a4517396251a2639b7e1abc0b1903defb22a885f9fc161ef7279c9e38482d37' 
  AND token = 'K8xysmHbYBM90XNBhFSLWh9zlj4oxSz6bgpwtriKQ7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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