SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e89fdb386fa8708f829c52d55a5164d9bd55ac8c9ac45e0f60b2c3ac9b09cb6' 
  AND token = 'z1OhpBu8/xl3XR+NGMU+FdJGZLPwYkjWgOp7oal6Ees=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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