SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0bf0d98fc95d434db4ba1c7b39a16849eb6724d3d2664f3c96a65b778e2a2d4' 
  AND token = '6xcQGTYBhVhJ0UWkAZNuEfpbsyXGV1GlbJTSdEmQbvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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