SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa5dc4c3aad566dd1170ab355a41734c8cbfb2caea5b30e2d3b8d929d2c9cfd6' 
  AND token = 'H+JiGvsulDLTdTIbObKR7PGLFBMI2/nrFI47ECndrYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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