SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f4b842ae95f56c3405f7c2ab71a691066487ec3672e26f40053e70ef2b172aa' 
  AND token = '+ek+NHyveaKvnZ/LNQxKetfaUfCXRtQEY+uslMxjxIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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