SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a20633d787913081d41bc713bbc3101e36b71f2b81a76851c74534802a6210ba' 
  AND token = 'vpvPSImNkskNbEy+BHTlZGoGDw23ScxXnEVWvtGvNk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}