SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8eafe54f83375a299cf43e63bb064ec4d1aaac3941a450f92cbc7ca8beaafc1f' 
  AND token = 'rN42GIjh2rwXEHuM1PEs+TlDeTRMOIcnXmp/GqtSDKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}