SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6db742447ed3dd1121d11111d848101a1f1303148fe04f0d4c4def4ba43b0063' 
  AND token = '7cGorVKYwGnLXD7oeQfEZRJgi7DwX8O2u832Kh1rYUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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