SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5301220dbaedf780c042bcddb8b41ac20ed5675c6610a26a2c4d4678b189d3d' 
  AND token = 'GlWygDRTa2Z7PPoPBiZzAQOSVKVSHzzS64A9ok0IkyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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