SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4c4d4be07cdda07efa1ce849b5258bb37b83354a022985d1a5530f490707888' 
  AND token = '4VcNnv90mMHEIQ2KOUzGD6/FyTmuJ1eZEWmbmXkJick=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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