SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff20189fe01bcaaa35a457a71c736bcbecb596493b076b7312441615f856d8ae' 
  AND token = 'D6AiymxYov7+bk0iQtplmIpL8FfHTg4Byoy/S/Iyyqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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