SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb633d491af287f91c3c05285fe82faf737d9b55e9969f161bba42c5c26d5af3' 
  AND token = 'fy1LyuLxVzwOyr1i6TDPhqcl7CLJbP47EmTnFlxa0n0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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