Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9fcfe170cc9a2623754ad6cf8b102c6094cd4c86417a0cc9d3b2ebedab1708a' 
  AND token = 'E1vUUyHqcIJMjJgFcMuWbjP7U8xnL+qL2vFb+TH4ftE=' 
  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"
    }
  }
}