SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7120991f6ed44b9bb0e6628bdbe650d26878b3ed66c8092bd172c51b4a426384' 
  AND token = '54fBAewljF76WOcFIKTNeX5APgKkgo4wuIPj7YOUcJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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