SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bf4ca1bbb3c34113a0ef6635254963daf803b4628f02802929af001d27d60e2' 
  AND token = 'Wwxjb8G+LVLfmpYV8MuFmhFNjS2DQHhJ37Mt0vf1KGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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